How can you amend a 30yr old death cert?

[copzgirl1171]

and does it matter in this case?

todayentertainment.today.com/_news/2012/08/22/13411812-natalie-woods-death-certificate-amended-by-coroner?lite

The document was amended earlier this month and shifts Wood's death from an accidental drowning to "drowning and other undetermined factors," according to a copy of the certificate obtained Tuesday by The Associated Press.
The amended document also now states that the circumstances of how Wood ended up in the waters off Catalina Island in November 1981 are "not clearly established."
The changes occurred nine months after sheriff's homicide investigators renewed their inquiry into Wood's death shortly before its 30th anniversary.
Chief of Detectives William McSweeney said the decision to amend the death certificate was ultimately made by the coroner's office, which has been instructed by detectives not to discuss the case. "I would just say undetermined is descriptive," he said.

[brit1017]

Death certificates generally have a cause of death and a manner of death. I would think that it would be inappropriate to change the cause of death, as that is determined at the time of autopsy, but the manner of death generally takes external factors into consideration, so I can see how that could change (ie the discovery of a suicide note) The cause of death in this case would be drowning, but if the manner of death was originally "accidental" and is now "undetermined", I would imagine that it would allow them to bring charges against someone in connection with her death.